The present disclosure relates generally to the field of cranes and other lifting machines designed to raise, lower, load, unload, or otherwise move cargo, materials, and other items.
A crane typically includes a main body or platform and a boom extending from the main body. The main body may be fixed or mobile. The boom supports a cable, which may be formed from metal wire, chains, rope, or other materials. A hoist or winch is used to wind and unwind the cable. The crane further includes a hook or other tool hanging from the end of the boom opposite to the main body by the cable. The hook is generally used to attach cargo, materials, or other items to the cable of the crane. Some cranes include a hook or other tool fastened to a rigid post or section, without a cable.
The sizes, loads, and forms of cranes vary widely. In some cases, the boom includes stages of extensions that slide telescopically from one another. The number of stages varies, and may include a main section with two extensions, or many more than two extensions. In other cases, the boom includes a jib pivotally fastened to an end of the boom, to increase the length of the boom. The jib may also include telescoping sections. In still other cases, the boom extends from the main body of the crane by way of an articulated arm that maneuvers the boom.